836
ROSENTHAL AND SCHWARTZXAN
leaving 2.3 g. of a brown solid mass, m.p. 140'. A solution of 0.5 g. of the latter was taken up in 10 ml. of benzene and passed through a column containing 15 g. of neutral alumina (Merck) to afford 0.05 g. of crude hydrocarbon (bcinzene eluent) and 0.30 g. of unchanged ketone (VII) (chloroform eluent). The former was recrystallized from 95% ethanol as pale yellow needles, m.p. 118-120", unchanged upon further recrystallization. This hydrocarbon (50 mg.) was dissolved in 2 ml. of benzene-hexane (50: 50) and passed through a column containing 5 g. of acidic alumina (hlerck). The first fraction (10 mg.) was recrystallized from 95% cbthanol to afford VI11 as colorless fine needles, m.p. 108-109°, &A:,; (log e) 235 mr (4.7), 244 (4.91, 256 (4.1), 266 (4.5), 277 (4.7), 313 (4.1), 327 (4.5), 343 (4.61,357 (3.5), 369 (2.8), and 377 (3.4). (Lit., m.p. 107-108°,11 112-113°12; the spectra were superimposable in all respects.12) The second fraction (20 mg.) was rccrystallized from 95% ethanol to afford VI as pale yellow plates, m.p. 123-124', A&; (log e ) 218 ma (4.6),228 (4.4),235 (4.5), 269 (4.4), 279 (4.6),290 (4.7), 311 (3.9), 325 (3.9), 340 (3.8), 356 (3.3), 367 (2.9), 374 (3.2). (Lit.,l'J m.p. 134O.) Anal. Calcd. for CloHl~:C, 94.97; H, 5.03. Found: C, 94.80; I3, 5.09.
VOL. 24
B. Zinc-sodium hydroxide reduction. A mixture of 1.0 g. of ketone (VII) and 8 g. of zinc dust in 60 mi. of 10% sodium hydroxide solution was covered with 10 ml. of l-hexanol and heated under reflux for 6 hr. The solution was evaporated and acidified with 6iV hydrochloric acid. The resulting black precipitate was filtered, dried, and pyrolyzed for 15 min. a t 280' and 0.5 mm. pressure. The yellow sublimate (0.30 g . ) was chromatographed on 10 g. of acidic alumina to afford 0.13 g. of hydrocarbon (VI) and 0.08 g. of unchanged ketone (VII). The former was recrystallized from 9570 ethanol as pale yellow plates, m.p. 123-124', undepressed on admixture with that prepared via method A.
Acknowledgment. The author acknowledges the technical assistance of W. B. White in recording some of the spectra. He wishes to thank Prof. Newman and Dr. Vollmann for their gifts of IX and VII, respectively. He also wishes to thank Drs. Phillips and Chatterjee for information concerning X prior to its publication. PITTSBURGH 13, PA,
[CONTRIBUTION FROM THE RESEARCH DEPARTMENT O F THE KOPPERS COMPANY, INC.]
Carboxylation of Propargyl Halides ROBERT 11.' ROSENTHAI,
AND
LOUIS H. SCHWARTZMAN
Received November 24, 1968 The reactions of propargyl halides with nickel carbonyl have been studied. Carboxylation of propargyl bromide a t 70' and atmospheric pressure yielded ethyl 3-bromo-3-butenoate (I). Partial reduction of I with LiAlH, yielded 3-bromo-3buten-1-01 which upon ozonolysis yielded formaldehyde. A mechanism is given which postulates the formation of an allenic ester, ethyl 2,3-butadienoate (11), intermediate. In the case of propargyl chloride both I1 and ethyl 3-chloro-3-butenoate (111) were isolated. Lower yields of product were obtained when the reaction was run under carbon monoxide pressure. This result is consistent with the hypothesis of \Vender that the first step of the reaction is the formation of an acetyleniccarbonyl complex and carbon monoside.
I n the course of investigations being carried out in our laboratories, propargyl halides were carboxylated with nickel carbonyl. The recent disclosure by Jones, Whitham, Whiting1 of similar work made it desirable for us to release our findings. According to Raphael2 propargylic bromides in ethanol react with nickel carbonyl and water to yield bromine-free allenic acids. In our laboratories when propargyl bromide in ethanol was caused to react with nickel carbonyl at 70" and atmospheric pressure, an evolution of heat took place and instead of a halogen-free allelic acids being formed, ethyl 3-bromo - 3 - butenoate, CH2=CBrCH2C02CzHb (I), was obtained in 217, yield. The characterization of I presented some interesting problems. Due to the presence of the bromine atom, infrared analysis could not distinguish whether the ester contained a terminal methylene group or 8 double bond conjugated with the c:rrbonyl group. Semimicro hydrogenation revealed that two moles -
(1) E. R. H. Jones, G . H. Whitham, and M. .'C Whiting, J. Chem. Soc., 4628 (1057).
(2) K. A. Raphael, Acelylene Compourds in Organic S y n thesis, Academic Press, N. Y., 1055, p. 138.
of hydrogen was absorbed per mole of compound. Although the compound did not give a positive halide test when tested directly with alcoholic silver nitrate, it was found to contain approximately 39% bromine when the solution formed by either hydrogenating the sample or heating it one hour with caustic, was analyzed for halide ion. Saponification equivalents of several samples averaged 190. Vapor phase chromatographic analysis indicated the presence of a single compound of 90+% purity. All these data were consistent with the ethyl ester of a moriobromobutenoic acid, which would have a molecular weight of 193 and would, under the conditions used, absorb two moles of hydrogen (hydrogenation of the double bond and hydrogenolysis of the bromine atom). The problem of which isomer was present, however, was as yet undecided. Therefore, the hydrogenated solution was saponified and yielded the potassium salt of an acid which was converted to n-butyro-p-toluide, and the p-bromo- and p-phenylphenacyl esters of ?+butyric acid. Thus the carbon skeleton was that of n-butane. The location of the halogen atom was assigned to the third carbon atom by the fact that
JUNE
1959
saponification of the ester followed by acidification with further refluxing yielded acetone. The reaction sequence is pictured as in equation (1).
Br 2HsO +
CH,=V-CHZ-C02-
i, -
+ CH~-C-CHI -COa
H
(1)
Despite the fact that infrared analysis suggested a terminal methylene group, this was riot confirmed by ozonolysis. The compound was ozonized but attempts to isolate formaldehyde either as the 2,4dinitrophenylhytlrazone or as the dimedone adduct failed. However, the presence of the terminal methylene group was established by the method of Lemieux and Rudloff3 which consisted of oxidizing the compound with a periodate-permanganate mixture at pH 7 and then observing the color formed by the addition of chromotropic acid to the formaldehyde formed. Partial reduction of I with lithium aluminum hydride yielded 3-bronio3-buten-1-01 which was characterized by infrared analysis, bromin? analysis, hydrogen and hydroxyl numbers, and preparation of a derivative. Ozonolysis of this compound in the presence of 2,il-dinitrophenylhydrazine yielded formaldehyde 2,4-dinitrophenylhydrazone. The mechanism for the formation of I can be visualized as follows :
CO
(11) ethyl 2,3-butadienoatr
H Br
I 1 1
H-C--C=CH*
COzCzHj (1)
I t was hoped that ethyl 2,3-butadieno:tte (11) could be isolatcd from the reaction mixture and caused to react with hydrobromic acid to form I and thus lend support to this mechanism. However, none was isolated from the propargyl bromide carboxylation mixture. Because of the well-known relationship of the rates of addition of hydrobromic Acid arid hydrochloric acid to double bonds, it wits hoped that I1 (formed from the analogous carboxylation of propargyl chloride) could be isolated before it reacted with the hydrochloric acid present. Consequently, propargyl chloride was carboxylated a t atmospheric pressure and small yields of both 11 and ethyl 3-chloro-3-buteno~tc (IIT) were isolated. I1 was idcntified by its infrared spectrum, hydrogen number, and saponification equivalent. The index of refraction of I1 was the same as re(3) It. U. Lemieux iind 1':. vori ItudlofT, C a 7 ~J . ('hcnz., 33, 1710 (1955).
837
CARBOXYLATION OF PROPARGYL HALlDES
ported by Eglenton et al.,4 but the boiling point (44"/130 mm.) differed from ours (92-94'/140 mm.). However, hydrolysis of I1 with dilute sodium hydroxide yielded 2,3-butadienoic acid, m.p. 6365", the same melting point rep2rted by them. 111, which was not either ethyl P-chlorocrotonate or -isocrotonate reported by Hatch and T'erry,', was characterized by the same sequence of reactions used to identify I. Some support for the mechanism was gotten from the fact that when hydrochloric acid was caused to react with 11, the only products obtained were I1 and 111. The low yield obtained in the carboxylation of propargyl chloride was believed to be due to the fact that the boiling point (65") of propargyl chloride was lower than the reaction temperature (70"). The carboxylation, therefore, was carried out in an autoclave and a 30% yield of a mixture of XI and I11 was isolated. No heat was used, an exotherm was avoided, and 88% of the product was 11. This work is comparable to that of Jones, Whitham, and Whiting2 in which they carboxylated 3-chloro-3-methyl-l-butynein the presence of sodium acetate buffer to remove the hydrochloric acid formed and obtained a 34% yield of 4-methylpenta-2,3-dienoic acid along with 1I yo of its ethyl ester. In the case of propargyl chloride they reported a 6% yield of buta-2,3-dienoic acid, but made 110 mention of an ester fraction. Several attempts were made to carboxylate propargyl chloride under an elevated carbon monoxide pressure (400-2000 p.s.i.g.) and it was found that considerably less carboxylation took place. These data indicate it is possible that carbon monoxide inhibits the carboxylation. This conclusion is analogous to that of Natta, Ercoli, Castellano, and Barbierie who, in a study of the hydroformylation reaction, found that above carbon monoxide partial pressures of 10 atm. the percent olefin conversion decreased with increasing pressure. They postulated that the first step involved the reaction of the olefin with cobalt carbonyl to form an olefincarbonyl complex and carbon monoxide. It is possible, therefore, that the first step of the carboxylation of acetylenic compounds with nickel carbonyl involves the reaction of the two compounds to form an acetylenic-carbonyl complex and carbon monoxide. This has been shown7 to be the case in the reaction of acetylenes and cobalt carbonyi as shown in equation (2). Carboxylations of R-C=C-R'
+ COZ(C0)8
____I_
----f
+
ltC?lt'Con(CO~a 2 GO (2)
(4) G. Eglenton, 15. R. H. Jon(Xs, G. H. Munsfield, and M. C . Whiting, J. C h m Soc., 3197 (L954). ( 5 ) I,. F. Iletch tml li 13. Perry, J . .In/. ('hem. Sac., 77, 1137 (1955). (6) G Natta, Ii. 15icoli, S. Csstc.IIano, ant1 F. H. Ihrbirri, J. .I*& ('h~nt SOC.,76, 4040 (1954). ( 7 ) I Wcnder, I€. W. Sternberg, H. Grtwificld, It. A. Friedel, J . Wotiz, anti 11. hI:Lrkby, J . A m ('hem. Soc., 76, 1457 (1954).
838
ROSEKTHAL AND SCIIWARTZMAN
propargyl chloride with cobalt carbonyl both in the absence of carbon monoxide and under elevated carbon monoxide pressure were attempted and yielded no carboxylation product. EXPERIMENTAL
Carboxylation of propargyl bromide. A mixture of freshly distillrd propargyl bromide (119 g., 1.0 m.), absolute ethanol (100 nil.), and concentrated hydrochloric acid (59.5 g., 0.6 m.) was placed into a 4necked flask having a stirrer, thermometer, dropping funnel, and condenser. Nitrogen was swept through the system while the stirred solution was heated to 70'. At this temperature a small portion of a solution of nickel carbonyl (39 g., 0.23 m.) in absolute ethanol (100 ml.) was added to the reaction mixture. After a short induction period an exothermic reaction took place and the solution was kept a t 70" (heating mantle removed) by the rate of addition of carbonyl solution. At the end of the reaction (1.5hr.) the temperature gradually dropped to 45'. Ether was added, the pot was heated, and everything; distilling off below 82' was discarded. The contents were cooled, dissolved in ether, and washed with 5 % sodium bicarbonate solution. The dried (magnesium sulfate) layer was distilled through a Gin. Vigreux column and yielded 46 g. (24%) of ethyl 3-bromo-3-butenoate boiling at 82" (23 mm.). The crude product was redistilled through a helix-packed Todd column (900 X 12 mm.) and there was obtained 33.2 g. of product bciling a t 85" (25 nun.); ny 1.4650. Infrared: 5.75 p (vs), 6.12 p (s), 8-9 p (vs), 11.1 f i
w. And. Cnlcd. for C6H802Br:Br, 41.4; Hydrogen No., 2.0;
Sapon. Equiv., 193. Found: Br (hydrogenation), 39.8, Br (caustic), 39.1; Hydrogen No., 1.9; Sapon. Equiv., 191. The experiment was repeated using acetic acid instead of hydrochloric acid and a 21% yield of the same product was obtained. Proof of struciure of ethyl S-bromo-9-butenoate. (a) Carbon skelebn. (1) The carboxylation product (13 g., 0.07 m.) was hydrogenated over pro-reduced platinum oxide catalyst a t atmospheric pressure and room temperature. The absorption was 1.9 moles of hydrogen per mole of compound. Solid potassium hydroxide (4 g., 0.07 m.) was added to the alcoholic ester solution arid the mixture was refluxed 1 hr, The ethanol was removed under reduced pressure to give 5.8 g. of solid. This potassium salt was converted by standard methods into the p-bromophcnacyl rster, the p-pheriylphenacyl ester, and the p-toluidide. Table I summarizes the results. The acid, therefore, was n-butyric acid. TL4BLE I
Derivative p-Bromophcnacyl ester p-l'lienylphenacyl ester p-Toluidide
Literature Valuc, M.P., "C. IsonObserved butyric Butyric M.P., .\rid .\rid "C. 77' 89' l0Gc
63' 8Jb 7:-$
f32-63e 79-80 68-70
a \IT. T,. .Judcfind and 15. 13. Reid, J . -4m. Chem. Soc., 42, 1055 (1920). P. W. Clutterbuck, 11. Itaistrick, and F. Ileuter, Biochem. J., 29, 880 (1%35). 1,. F. Fiesrr, J. L. Hartwrll, and A. M.Seligman, J . A m . Chenl. Soc., 58, 1226 (lHJ(i). 1'. W. Robertson, J . Chcn~.SOC.,115, 1220 (1919). huthcntic sample mrltcd a t 61 -62'; mixed m.p. with uriknown sample, 61-62'.
(2) Carboxylation product (50 g., 0.26 m.) vias dissolved in 125 ml. anhydrous ether and over B period of 3 hr. lithium aluminum hydride (9.5 g., 0.25 m.) was addcd with gentle
VOL.
24
refluxing. The reaction was stirred overnight and water was added to the mixture at such a rate that there was gentle refluxing. The solution was filtered, the filtrate was dried (magnesium sulfate), distilled under reduced pressure through a 6-in. Vigreux column, arid there was isolated 11.6 g. of 3-bromo-3-buten-1-01 boiling a t 80-85" (16 mm.) ; ny 1.4949. Anal. Calcd. for C4Hi0Br: Br, 53.0; Hydrogen No., 2.0; Hydroxyl No., 1.0. Found: Br, 53.0; Hydrogen No., 2.1; Hydroxyl No., 1.0. 3-Bromo-3-buten-1-01 was converted into its 3,5-dinitrobenzoate which after two recrystallizations (ethanol-water) melted a t 57.5-58.0'. Anal. Calcd. for C&N,O&r: C, 38.3; II, 2.6; N, 8.1. Found: C, 39.0; H, 2.7; N, 8.3. 3-Bromo-3-buten-1-01 (1.1 g.) was dissolved in 25 ml. benzene and completely hydrogenated over pre-reduced platinum oxide catalyst a t atmospheric pressure and room temperature and 2.0 moles of hydrogen was absorbed per mole of compound. The catalyst was removed by filt,ratiou and 1 g. of alpha-naphthyl isocyanate was added. The solution was warmed on the steam bat,h and the benzene removed by evaporation. n-Hexane was added and a high melting solid separated. The filtratc was concentrated and a solid melting a t 60-65' separated. Recrystallization three times from n-hexane rhised the m.p. t.o 68-69'. The melting point of a mixture of this compound and the alpha-naphthylurethane of n-butanol (m.p. 70') was 68-69'. (b) Location of bromine atom. Ethanol (40 ml.) was added to a mixture of propargyl bromide carboxylation product (10 g., 0.05 m.) and 150 ml. water containing 5 g. (0.13 m.) sodium hydroxide until the soliltion was homogeneous and the mixt,iire was allowed to stand overnight a t room temperature. Concentrated hydrochloric mid (15 ml.) was added and the solution was heated I hr. on the steam bath. The solution was coolecl and a solution of 10 g. (0.05 m.) of 2,il-dinitropheriylhydra~ine iii 20 ml. concentrated sulfuric acid arid 5 ml. water was added. There was obtained 5 g. (0.02 m.) of acetone 2,4-dinitrophenylhydrazoiic?melting a t 135-126'. No depression was obscrvcd on the melting point of a mixture of it and authentic acetone 2,4-dinitrophenylhydmzone. (e) Location of the double bond. (f) Permanganate-periodate oxidation. A sample of the compound was oxidized according to the method of Lemieux and Rudloff . 3 Propargyl bromide carboxylation product (10 ml. of a solution made by diusolving 3 drops of compound in 300 ml. water) WBA adjusted to pH 7.0-7.6 with 0.lN potassium carbonate. Then 10 nil. of 0.02M potassium meta-periodate and 1 ml. of 0.005N KMnOc wcrc added. The solution was made up to 25 ml. and a 5 ml. aliquot was removed and added to a mixture of 2 ml. of 111.1 sodium arsenite and 2 ml. of 221' sulfuric acid. The solution was allowed to stand 15 min. and then a 1 ml. aliquot was added to 10 ml. of chromotropic acid reagent (1 g. of acid dissolved in 100 ml. of H20 and the solution made to 500 mi. with 2 : 1 v/v sulfuric acid-water mixture) and heated on a boiling water bath for 30 min. An intense violet color appeared signifying the presence of a terminal methylene group. ( 2 ) Ozonolysis of 6bro7no-S-buten-1-ol. 3-Bromo-3-buten1-01, (1 g.) W ~ L H dissolved in 100 ml. of methanol and this solution was ozonized (Welsbach Gorp. Model T-23 Laboratory Ozonator) a t 0' for 100 min. Then 1.5 g. of 2,+dinitrophenylhydrazine in 5 nil. of concentrated sulfuric acid was added. A small amount of amorphous solid precipitated. The addition of water to the filtrate yielded a ycllow compound melting at 140-148'. Iterrystallization from etlinnol (charcoal) gave a solid melting a t 16&-168°. The melthg point, of a mixture of it and acetaldehyde 2,4-dinit,rophenylhydrazone (m.p. 167-168') showed melting point dcpression, m.p. 130+"; but with authentic formaldehyde 2,4dinitrophenylhydraxone (m.p. 166-167') no depression, m.p, 166-167". Stoichiometric carboxylation of propargyl chloride with
JUNE
1959
CARBOXYLATION OF PROPARGYL HALIDES
nickel carbonyl. Propargyl chloride (50 g., 0.66 m.), acetic acid (30 g., 0.66 m.), water (12 g., 0.66 m.), 95% ethanol (38 g., 0.83 m.), and hydroquinone (trace) were placed in Dry Ice and then placed in a stainless steel autoclave of 300 ml. capacity. Nickrl carbonyl (26 g., 0.15 m.), was frozen in a test tube and the open tube carefully placed in the autoclave. The autoclave was sealed and rocked for 1 hr., during which time no heat evolution was observed. The contents were extracted with ether, the ether solution dried (magnesium sulfat,e), stripped, and the residue distilled under reduced pressure (nitrogen bleeder) through a 6-in. Vigreux column. There was obtained 21 g. of a mixture which was 88% ethyl 2,3-butadienoate (11) and 12% ethyl 3-chloro-3-butenoate (111).A portion of the product was distilled through a Todd column (900 X 12 mm.) at reduced pressure and compounds I1 and I11 were obtained. I1 boiled a t 92-94' (140 mm.); n 2 1.4578. It exhibited infrared absorptions a t 5.06 and 5.13 microns characteristic of the terminal allenic group, and a t 5.82, 7.95, and 8.5 microns characteristic of an alpha,beta-unsaturated ester. Anal. Calcd. for CSHSO~:C1, 0.0; Hydrogen KO.,2.0; Sapon. Equiv., 112. Found: C1, 0.3; Hydrogen Yo., 1.9; Sapon. Equiv., 121. Saponification of I1 for 10 min. on a steam bath with 1 N sodium hydroxide, followed by acidification to pH 4.5 with dilute sulfuric acid and extraction with ether yielded 2,3butadienoic acid, m.p. 63-65' (4). I11 boiled a t 67' (75 mm.); ng 1.4389. It exhibited infrared absorptions a t 5.76 and 8.40 microns characteristic of an ester group. Absorptions a t 6.12 and 11.16 microns indicated the presrnce of a branched terminal vinyl group. No allenic group absorption could be detected in this sample. Anal. Calcd. for C6H90&1: C1, 23.6; Hydrogen No., 2.0; Sapon. Equiv., 74.0. Found: C1, 23.5; Hydrogen KO.2.1; Sapon. Equiv., 75.6. Reaction of ethyc' 2,J-butudienoate (11) with concentrated hydrochloric acid. IC (3.1 g., 0.03 m.) and 12N hydrochloric acid (3.E ml., 0.03 m.) were mixed Rith 95% ethanol (10 ml.) at room temperature with stirring. After being allowed to sit overnight, the solution was warmed on a steam bath for 15 min. and allowed to sit 1 hr. while cooling. FTater was added, the layers wrre separated, and the organic layer was washed again with water. The water layers were combined and found by titration to contain 0.016 m. hydrochloric acid, i.e., about half had reacted. The organic layer (2.3 g.) was dissolved in ether, extracted with 5% sodium bicarbonate, dried over magnesium sulfate, filtered, and concentrated. An ester residue (0.7 g.) was obtained u-hich infrared analysis indicated was a mixture of I1 and 111. Proof qf structure of ethyl 3-chloro-3-butenoate (111). (a) Carbon skeleton. A sample of compound I11 was hydrogenated and saponified in a manner similar to that done to ethyl 3-bromo-3-butenoate (see above). The p-bromo-
539
phenacyl ester made from the sodium salt of the acid melted at 63-64'. The melting point of a mixture of it and authentic p-bromophenacyl-n-butyrate showed no depression. (b) Location of the chlorine atom. A portion of the ethyl 3-chloro-3-butenoate was saponified, acidified, and then treated with 2,Pdinitrophenylhydrazine as was done was to ethyl 3-bromo-3-hutenoate (sre above). There was obtained a 2,4-dinitrophenylhydraeonemelting at 122-125". The melting point of a mixture of it and authentic acetone 2,4-dinitrophenylhydrazone showed no depression. Catalytic carboxylation of propargyl chloride with nickel carbonyl. A series of carboxylations was run and the following is a description of a typical experment. Propargyl chloride (50 g., 0.66 m.), acetic acid (30 g., 0.66 m.), water (12 g., 0.66 m.), 95% ethanol (48 g., 1.04 in.), and hydroquinone (trace) were placed in Dry Ice and then placed in a stainless steel autoclave of 300 ml. capacity. Sickel carbonyl (2.6 g., 0.02 m. ), was frozen in a test tube and the open tube placed in the autoclave and the autoclave sealed. The system mas charged with 2000 p.s.i.g. carbon monoxide and the system was heated and rocked a t 90' for 2 hr. The cold absorption was 1400 p.s.i. The contents (26 g.) were extracted with ether, the ether solution dried (magnesium sulfate), and the ether rrmoved under reduced pressure (nitrogen bleeder), The residue was distilled under reduced pressure through a E-in. Vigreux column and yielded 13 g. (E'%)of material boiling a t 75-80' (30 mm.), ng 1.4330. The product by analysis was 7370 ethyl 3-chloro-3-butcnoate. Attempted carboxylation of propargyl chloride with cobalt carbonyl. Cobalt carbonyl solution in benzene (0.1 g./ml.) was made from cobalt carbonate and CO:H* (1:1) according to the directions of R'ender, Greenfield, and Orchin.8 Proppargyl chloride was treated with cobalt carbonyl in reactions analogous to those done with nickel carbonyl and in neither the stoichiometric nor the catalytic reaction was an insoluble carboxylation product obtained.
Acknowledgment. The authors are indebted to the General Aniline and Film Corp. for the generous supply of propargyl chloride and bromide. We acknowledge also the help of Dr. Charles Teitelbaum of the Battelle Memorial Institute for the vapor phase chromatographic analysis reported and the Analytical Group of the Koppers Go., with the aid of Mrs. Jean W. Biss, for the other analyses conducted. VERONA, PA.
(8) I. Wender, H. Greenfield, and M. Orchin, Chem. SOC.,73, 2656 (1957).
J. Am.
